Flutter : Wrong index Delete inside List.sort() descending

Question

I have listviewBuilder , I want sorting my listview based on DateCreate with this code

taskList.sort((a, b) => -a.dateCreate.compareTo(b.dateCreate));

Everything is fine, i can see my list Sort (Descending) based on DateCreate, But the problem is everytime i delete/update the list, the action is wrong index!

It's without Sort (Working)

It's using Sort (Failed !!!)

If you see in Failed gif , I want deleted index 0 , But index 1 is deleted. If without Sort list is fine.

I surely passing right index, because in Working gif, i can successfully delete right index.

How can i fix this ?

ListviewBuilder Source Code :

SingleChildScrollView(
          child: Column(
            children: <Widget>[
              WatchBoxBuilder(
                box: Hive.box("task_box"),
                builder: (ctx, box) {
                  if (box.isEmpty) {
                    return Container(
                      margin: EdgeInsets.symmetric(
                        vertical: mqHeight / 8,
                        horizontal: 8,
                      ),
                      height: mqHeight / 3.5,
                      width: double.infinity,
                      alignment: Alignment.topCenter,
                      decoration: BoxDecoration(
                        image: DecorationImage(
                          fit: BoxFit.cover,
                          image: const AssetImage("assets/images/empty.png"),
                        ),
                      ),
                      child: Text(
                        'Task Empty , Add Someone',
                        style: textTheme.title
                            .copyWith(color: Colors.black.withOpacity(.5)),
                        textAlign: TextAlign.center,
                      ),
                    );
                  } else {
                    final taskList = box.values.toList().cast<TaskModel>();
                    taskList
                        .sort((a, b) => -a.dateCreate.compareTo(b.dateCreate));
                    return Container(
                      margin: EdgeInsets.symmetric(
                        vertical: mqHeight / 8,
                        horizontal: 8,
                      ),
                      child: ListView.builder(
                        shrinkWrap: true,
                        itemCount: taskList.length,
                        physics: NeverScrollableScrollPhysics(),
                        itemBuilder: (BuildContext context, int index) {
                          final taskValue = taskList[index];

                          return CardOddCustom(
                            idTask: taskValue.idTask,
                            codeIcon: taskValue.codeIcon,
                            titleTask: taskValue.titleTask,
                            imagePath: taskValue.imageTask,
                            dateCreate: taskValue.dateCreate,
                            indexTask: index,
                          );

                        },
                      ),
                    );
                  }
                },
              )
            ],
          ),
        ),

Deleting Code

  void deleteCategory({@required int indexBox}) async {
    final hiveBox = Hive.box(taskBox);
    await hiveBox.deleteAt(indexBox);
    notifyListeners();
  }

Onpressed Function :

class CardOddCustom extends StatefulWidget {
  final DateTime idTask;
  final String titleTask;
  final String imagePath;
  final DateTime dateCreate;
  final int codeIcon;
  final int indexTask;
  CardOddCustom({
    this.idTask,
    this.titleTask,
    this.imagePath,
    this.dateCreate,
    this.codeIcon,
    this.indexTask,
  });

  @override
  _CardOddCustomState createState() => _CardOddCustomState();
}

class _CardOddCustomState extends State<CardOddCustom> {
 return InkResponse(
      onLongPress: () =>
          taskProvider.deleteCategory(indexBox: widget.indexTask),
      child: Card(
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.only(
            topRight: Radius.circular(80),
            bottomRight: Radius.circular(80),
          ),
        ),

Share the code snippet of deleting item

Vamsi
– Vamsi

2020-01-05 15:14:34 +00:00
Commented Jan 5, 2020 at 15:14 — Vamsi
– Vamsi, Commented Jan 5, 2020 at 15:14
@Vamsi Please see my updated.

Zeffry Reynando
– Zeffry Reynando

2020-01-06 00:33:26 +00:00
Commented Jan 6, 2020 at 0:33 — Zeffry Reynando
– Zeffry Reynando, Commented Jan 6, 2020 at 0:33

chunhunghan · Accepted Answer · 2020-01-06 06:38:31Z

1

taskList is a copy of Hive.box

taskList = box.values.toList().cast<TaskModel>();

when you do taskList.sort, Hivebox data still keep in original sequence

taskList.sort((a, b) => -a.dateCreate.compareTo(b.dateCreate));

You do not use box.put or box.putAll to persist the change
When you do hiveBox.deleteAt, it actually with sequence in HiveBox

await hiveBox.deleteAt(indexBox);

You can use key when you do put/get/delete

Edit
In offical example , the key is the same when you do put
"dave" is key for put/get/delete

import 'package:flutter/material.dart';
import 'package:hive/hive.dart';
import 'package:path_provider/path_provider.dart';

class PersonAdapter extends TypeAdapter<Person> {
  @override
  final typeId = 1;

  @override
  Person read(BinaryReader reader) {
    var numOfFields = reader.readByte();
    var fields = <int, dynamic>{
      for (var i = 0; i < numOfFields; i++) reader.readByte(): reader.read(),
    };
    return Person()
      ..name = fields[0] as String
      ..age = fields[1] as int
      ..friends = (fields[2] as List)?.cast<String>();
  }

  @override
  void write(BinaryWriter writer, Person obj) {
    writer
      ..writeByte(3)
      ..writeByte(0)
      ..write(obj.name)
      ..writeByte(1)
      ..write(obj.age)
      ..writeByte(2)
      ..write(obj.friends);
  }
}

@HiveType(typeId: 1)
class Person {
  @HiveField(0)
  String name;

  @HiveField(1)
  int age;

  @HiveField(2)
  List<String> friends;

  @override
  String toString() {
    return '$name: $age';
  }
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  var dir = await getApplicationDocumentsDirectory();
  Hive
    ..init(dir.path)
    ..registerAdapter(PersonAdapter());

  var box = await Hive.openBox('testBox');

  var person = Person()
    ..name = 'Dave'
    ..age = 22
    ..friends = ['Linda', 'Marc', 'Anne'];

  var current = DateTime.now().toString();
  await box.put(current, person);

  print(box.get(current)); // Dave: 22
}

edited Jan 6, 2020 at 6:38

answered Jan 6, 2020 at 3:05

chunhunghan

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10 Comments

Zeffry Reynando Over a year ago

await hiveBox.deleteAt() only accept int, but my type idTask is DateTime it's not suits, but i try change to await hiveBox.delete(idTask) it's not working. nothing happens

chunhunghan Over a year ago

In offical example , the key is the same when you do put, how do you deal with put? you can use it as key , in example 'dave', you can see my edited answer.

Zeffry Reynando Over a year ago

It's make sense, i use await hiveBox.add() to adding data. gist.github.com/zgramming/6ac43f9d697892dfd750f3c13c5d634d

chunhunghan Over a year ago

/// Saves the [value] with an auto-increment key. Future<int> add(E value); source code say add use auto-increment key

chunhunghan Over a year ago

In your case, I would suggest use put(key, your data) and pass this key to delete function

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Flutter : Wrong index Delete inside List.sort() descending

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